English verb conjugation
COULD CHECKER

Regular verb: checker - checkered - checkered

Affirmation

Simple form	V-ing form
I could checker you could checker he could checker we could checker you could checker they could checker	I could be checkering you could be checkering he could be checkering we could be checkering you could be checkering they could be checkering
Perfect	V-ing perfect
I could have checkered you could have checkered he could have checkered we could have checkered you could have checkered they could have checkered	I could have been checkering you could have been checkering he could have been checkering we could have been checkering you could have been checkering they could have been checkering

Negation

Simple form	V-ing form
I couldn't checker you couldn't checker he couldn't checker we couldn't checker you couldn't checker they couldn't checker	I couldn't be checkering you couldn't be checkering he couldn't be checkering we couldn't be checkering you couldn't be checkering they couldn't be checkering
Perfect	V-ing perfect
I couldn't have checkered you couldn't have checkered he couldn't have checkered we couldn't have checkered you couldn't have checkered they couldn't have checkered	I couldn't have been checkering you couldn't have been checkering he couldn't have been checkering we couldn't have been checkering you couldn't have been checkering they couldn't have been checkering

Interrogative form

Simple form	V-ing form
could I checker? could you checker? could he checker? could we checker? could you checker? could they checker?	could I be checkering? could you be checkering? could he be checkering? could we be checkering? could you be checkering? could they be checkering?
Perfect	V-ing perfect
could I have checkered? could you have checkered? could he have checkered? could we have checkered? could you have checkered? could they have checkered?	could I have been checkering? could you have been checkering? could he have been checkering? could we have been checkering? could you have been checkering? could they have been checkering?

Interro-negative form

Simple form	V-ing form
couldn't I checker? couldn't you checker? couldn't he checker? couldn't we checker? couldn't you checker? couldn't they checker?	couldn't I be checkering? couldn't you be checkering? couldn't he be checkering? couldn't we be checkering? couldn't you be checkering? couldn't they be checkering?
Perfect	V-ing perfect
couldn't I have checkered? couldn't you have checkered? couldn't he have checkered? couldn't we have checkered? couldn't you have checkered? couldn't they have checkered?	couldn't I have been checkering? couldn't you have been checkering? couldn't he have been checkering? couldn't we have been checkering? couldn't you have been checkering? couldn't they have been checkering?